http://www.cfsan.fda.gov/~frf/rfe0.html
Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration
The Regulatory Fish Encyclopedia (RFE) is a compilation of data in several formats that assists with the accurate identification of fish species. It was developed to help federal, state, and local officials and purchasers of seafood identify species substitution and economic deception in the marketplace. The RFE includes high-resolution photographs (jpeg format) of whole fish and their marketed product forms (such as fillets) which may be used for visual comparison.